MANILA, Philippines — Six graduates of the Philippine National Police Academy’s (PNPA) Maragtas Class of 2018 were beaten up by their underclassmen after the graduation rites on Wednesday where President Duterte was the guest of honor and speaker, a ranking police official said yesterday.

The new officers with the rank of inspector, whose identities were not disclosed by the source, suffered contusions and lacerations.

They are now recuperating in an undisclosed hospital, the source said.

The source disclosed the incident happened between 4 p.m. and 5 p.m. at the PNPA barracks in Silang, Cavite while the graduates were packing their belongings.

The group of cadets from the lower classes arrived and attacked them an hour after Duterte left the PNPA for another official engagement.

“We think this is a personal grudge on the part of the underclassmen,” the source said in a phone interview, adding the cadets most likely wanted to get even with their upperclassmen for the hardships they endured at the academy.

PNPA officials are now conducting an investigation to determine who among the cadets were involved in the attack, as not a single cadet is willing to talk, the source said.

He said the son of Philippine National Police (PNP) chief Director General Ronald dela Rosa did not take part in the attack as he was in another building when the incident occurred.

The PNPA has submitted a report to the Philippine Public Safety College while the Calabarzon police launched an investigation into the incident as ordered by regional police director Chief Superintendent Ma-o Aplasca.

Aplasca did not reveal the exact nature of the incident as investigators from the Silang police were still gathering information.

He confirmed the victims were still recuperating at a hospital.

A police officer at the Silang Municipal Police Station said in a phone interview their commander, Superintendent Rommel Javier,

responded to an incident at the PNPA together with investigators.

When sought for comment, Javier said he lacked the authority to disclose the information they obtained about the incident.

President Duterte is seeking common ground with Beijing on the planned joint exploration in Philippine waters and has not abandoned the 2016 arbitral court ruling favoring the Philippine position on the South China Sea, Malacañang told Vice President Leni Robredo yesterday.

Malacañang on Saturday slammed Vice President Leni Robredo for criticizing President Rodrigo Duterte’s openness to ignore the Philippines’ legal victory in the South China Sea and seal an energy deal with Beijing, saying she needs new advisers who can comprehend the maritime row.

The US Navy said that one of its destroyers had sailed close to the Chinese-controlled Paracel Islands in the South China Sea on Friday, asserting international freedom of navigation rights in the contested waters.

Under Philippine law, President Rodrigo Duterte does not have the authority to "set aside" the July 2016 ruling issued by the Permanent Court of Arbitration, Supreme Court Senior Associate Antonio Carpio said.